KR20110033176A - Heat and moisture exchange unit - Google Patents

Abstract

The present invention is directed to a heat and moisture exchange (HME) unit 50 comprising a housing 52, a heat and moisture retention medium 54 (HM medium), and a valve mechanism 56. The housing 52 forms an intermediate section 62 extending between two ports 58, 60 and forming first and second flow paths. HM medium 54 is maintained along the first flow path. The valve mechanism 56 is movably retained in the housing 52 and includes a blocking member 100 that is switchable between opposing first and second maximum points of movement. At the first maximum point of travel, the obstruction member 100 closes the second flow path to allow air flow only through the first flow path. At the second maximum point of travel, the obstruction member 100 allows air flow through both the first and second flow paths. The HME unit 50 is simple to use and provides an effective bypass state where air flows freely around the HM medium 54.

Description

Heat and Moisture Exchange Units {HEAT AND MOISTURE EXCHANGE UNIT}

The present invention relates to heat and moisture exchange ("HME") units useful in patient breathing circuits. In particular, the HME unit of the present invention provides a bypass configuration that is connectable to the breathing circuit and that allows the air flow to selectively pass through the HME unit with minimal interaction with the stored heat and moisture retention medium.

The use of respirators and breathing circuits to assist patient breathing is known in the art. Respirators and breathing circuits provide mechanical assistance to patients who have difficulty breathing on their own. During surgery and other medical procedures, patients are often connected to a ventilator to provide breathing gas to the patient. One disadvantage of such breathing circuits is that the air to be delivered does not have an appropriate humidity level and / or temperature for the patient's lungs.

To provide the patient with air with the desired humidity and / or temperature, the HME unit can be fluidly connected to the breathing circuit. In view of reference, “HME” is a generic term and may include a simple condenser humidifier, a hygroscopic condenser humidifier, a moisture repellent condenser humidifier, and the like. In general, an HME unit consists of a housing that includes a layer of heat and moisture retention medium or material (“HM medium”). Such materials retain the moisture and heat from the exhaled air from the patient's lungs and then have the ability to deliver the captured moisture and heat to the ventilator-providing air of inspiratory breathing. The HM media may be untreated or formed of foam or paper or other suitable material, for example treated with a hygroscopic material.

Although the HME unit addresses the heat and humidity issues associated with the ventilator-providing air within the breathing circuit, other drawbacks may exist. For example, it is quite common to introduce aerosolized drug particles into the breathing circuit (eg, via a nebulizer) for delivery to a patient's lungs. However, if the HME unit is present in the breathing circuit, the drug particles will not easily traverse through the HM medium and therefore will not be delivered to the patient. In addition, the HM medium may be blocked with droplets of liquid medication, which in some cases leads to elevated resistance of the HME unit. One approach to solving this problem is to remove the HME unit from the breathing circuit when introducing the aerosolized medicament. This is time consuming and error prone and can cause a loss of recovered lung volume when the circuit is depressurized. Alternatively, various HME units have been proposed that include complex bypass structures / valvees that selectively and completely isolate HM media from the air flow path. For example, existing bypassed HME units employ bypass structures that are internal or pass through the HM media. While feasible, these and other bypassed HME units are difficult to operate (eg, require a guardian to rotate two frictionally fitted housing units relative to each other) and / or are relatively complex and therefore expensive.

In light of the above, there is a need for an improved HME unit having an HM media bypass feature that addresses one or more of the problems associated with conventional bypass HME units.

Some aspects according to the present invention relate to a heat and moisture exchange (HME) unit comprising a housing, a heat and moisture retention medium (HM medium), and a valve mechanism. The housing forms a first port, a second port, and an intermediate section. The intermediate section extends between the first and second ports and forms first and second flow paths that fluidly connect the first and second ports. HM medium is maintained in the intermediate section along the first flow path. The valve mechanism is movably retained in the housing and includes a blocking member that is switchable between opposing first and second maximum points of movement. In this regard, the HME unit is configured such that at the first maximum point of movement, the obstruction member closes the second flow path to allow air flow through only the first flow path. At the second maximum point of travel, the obstruction member allows air flow through the first and second flow paths. In this configuration, the HME unit is compact and simple to use, but provides an effective bypass state where air flows freely around the HM medium. In some embodiments, the first flow path is U-shaped in cross section and the HM medium is arranged in the first flow path such that the air flow passes through opposing major surfaces of the HM medium. In another embodiment, the HME unit has a check valve plate arranged to permit air flow through the second flow path in the first flow direction and prevent air flow through the second flow path in the second opposite flow direction. Additionally included.

Another aspect according to the principles of the present invention relates to an HME unit comprising a housing, an HM medium, and a valve mechanism. The housing includes an intermediate section extending between the first and second ports. The HM medium defines opposing first and second sides, and is disposed within the housing such that the first side is in fluid facing the first port and the second side is in fluid facing the second port. The valve mechanism includes a blocking member movably assembled in an intermediate section of the housing, fluidly between the first side and the first port of the HM medium. In this regard, the blocking member is switchable from the HME position where the blocking member completes the flow path from the first port, through the HM medium, to the second port, and closes the bypass flow path around the HM medium. In addition, the HME unit is configured such that at any position of the blocking member relative to the housing, at least a portion of the first side of the heat and moisture medium remains fluid open relative to the first port. In this configuration, the HME unit has a compact configuration, but can provide an effective bypass state in which the air flow moves freely around the HM medium.

Another aspect according to the invention relates to an HME unit comprising a housing, an HM medium, a secondary filter, and a valve mechanism. The housing forms an intermediate section extending between the first and second ports, and the intermediate section forms the first and second flow paths. The HM medium and the secondary filter are kept along the first flow path, away from the second flow path. The valve mechanism is movably assembled in the housing and includes a blocking member that is switchable between the first and second positions. In the first position, the first flow path is open and the second flow path is closed. In the second position, at least the second flow path is open. In this configuration, the HME unit can serve as the HMEF, where the secondary filter is relatively large compared to conventional bypass HMEF units, resulting in higher filter efficiency.

1 is a simplified diagram of an exemplary patient breathing circuit in which an HME unit in accordance with the principles of the present invention is useful.
2 is a simplified diagram of another exemplary breathing circuit in which an HME unit in accordance with the principles of the present invention is useful.
3A is a perspective view of an HME unit in accordance with the principles of the present invention in HME mode.
3B is a perspective view of the HME unit of FIG. 3A in bypass mode.
4A is a longitudinal cross-sectional view of the HME unit of FIG. 3A.
4B is a longitudinal cross-sectional view of the HME unit of FIG. 3B.
4C is a side cross-sectional view of the HME unit of FIG. 3A.
5 is a side cross-sectional view of the HME unit of FIG. 3A, showing an optional resistance indicator.
6 is a top, side perspective view of another HME unit in accordance with the principles of the present invention.
7A is a longitudinal cross-sectional view of the HME unit of FIG. 6 in the HME mode.
FIG. 7B is a longitudinal cross-sectional view of the HME unit of FIG. 6 in bypass mode. FIG.
8 and 9 are cross-sectional views showing a portion of another HME unit in accordance with the principles of the present invention.
10 and 11 are cross-sectional views showing a portion of another HME unit in accordance with the principles of the present invention.
12 and 13 are simplified cross-sectional views showing a portion of another HME unit in accordance with the principles of the present invention.
14 and 15 are simplified cross-sectional views showing a portion of another HME unit in accordance with the principles of the present invention.

As described in detail below, aspects according to the principles of the present invention relate to HME units useful in patient breathing circuits. In terms of reference, FIG. 1 shows one such breathing circuit 10 that includes a number of flexible tubing segments connected between the patient 12 and a ventilator (not shown). The breathing circuit 10 of FIG. 1 is a dual branch breathing circuit and may comprise a source 14 of pressurized air, an HME unit 16 (shown in block form), and a nebulizer 18 according to the invention. have.

With one non-limiting example of the breathing circuit 10 in mind, a patient tube 20 is provided that connects the patient 12 to the HME unit 16. The end of the patient tube 20 that connects with the patient 12 may be an endotracheal tube that extends into the patient's lungs through the patient's mouth and throat. Alternatively, it can also be connected to a tracheostomy tube (not shown in FIG. 1 but indicated 46 in FIG. 2) that provides air to the patient's throat and into the patient's lungs. A connector 22, for example a Y-connector, extends on the opposite side of the HME unit 16. Y-connector 22 may be connected to an additional tubing, for example an exhalation tube 24 (generally referred to as an “exhalation branch”) that allows exhaled air to leave the breathing circuit 10. A second tube 26 (generally referred to as an “intake branch”) can serve as a nebulizer tube and is connected to the nebulizer 18. Nebulizer 18 is in turn connected to intake branch 26 via connector 28, for example a T-connector. The T-connector 28 is connected to a ventilator (not shown) at the opposite end of the intake branch 26. Nebulizer 18 is in turn also connected to a source of pressurized air via air tube 30.

For further reference, FIG. 2 shows an alternative breathing circuit 40 in which the HME unit 16 of the present invention is useful. The breathing circuit 40 is a single branch breathing circuit that serves to fluidly connect the ventilator (not shown) with the patient 12 and includes a nebulizer 18 and a source of pressurized air 14. In a single branch breathing circuit 40, a patient tube 20 is again provided that fluidly connects the patient 12 with the HME unit 16. A single tube 42 extends from the HME unit 16 opposite the patient 12 and is fluidly connected to the nebulizer 18 via the T-connector 28. A ventilator (not shown) is connected directly to the T-connector 28 via a tube 44. If desired, a single branch breathing circuit 40 (and the double branch breathing circuit 10 of FIG. 1) may be connected to the tracheostomy tube 46.

The present invention contemplates the use of various types of nebulizers 18. In one exemplary nebulizer 18, a medicament is provided that is dissolved in sterile water and placed in a reservoir provided within the nebulizer 18. The pressurized gas blown across the atomizer in the nebulizer 18 is provided to the nebulizer 18. The force of the gas on the atomizer pulls the chemical liquid from the drug reservoir along the side of the nebulizer 18 by capillary action, providing a stream of chemical liquid in the atomizer. When the chemical liquid hits the stream of air transported from the atomizer, the liquid is atomized into a plurality of small droplets. The force of the air pushes this nebulized mixture of air and drug solution into the breathing circuit 10, 40 and to the patient 12, where the medicament is provided to the patient's lungs. The use of medicament administration in this procedure has been found to be highly effective in providing medicament to patients through the lungs. Metered dose inhalers may also be used to provide medication 12 in the air to the patient 12.

With the above general description of the breathing circuit in mind, one configuration of the HME unit 50 useful as the HME unit 16 (FIGS. 1 and 2) is shown in FIGS. 3A and 3B. HME unit 50 includes housing 52, heat and moisture medium 54 (HM medium) (hidden in FIGS. 3A and 3B but shown in FIG. 4A), and valve mechanism 56 (generally referred to). Include. Details on the various components are provided below. In a general aspect, however, the housing 52 forms a first port 58, a second port 60, and an intermediate section 62. HM medium 54 is retained in intermediate section 62. Housing 52 fluidizes ports 58, 60, including a first flow path through HM medium 54 and a second flow path (eg, on the side of HM medium) around HM medium 54. To form flow paths that connect. In this regard, the valve mechanism 56 is operable to specify the path through which air flow will occur at least primarily. In terms of reference, FIG. 3A shows the HME unit 50 in HME mode, and FIG. 3B shows the HME unit 50 in bypass mode as described below.

The housing 52 comprising the flow path formed thereby is further shown in FIGS. 4A and 4B (FIG. 4A shows the HME mode of FIG. 3A and FIG. 4B shows the bypass mode of FIG. 3B). As shown, the intermediate section 62 extends between the first and second ports 58, 60. For the upright orientation of FIGS. 4A and 4B, the middle section 62 forms an upper outer portion or wall 70, a lower outer portion or wall 72, and at least one inner partition 74. In some configurations, the bottom wall 72 is provided as part of the first housing segment 76 that is removably mounted to the second housing segment 78 that provides the ports 58, 60 and the top wall 70. . In any case, the HM medium 54 fits within the intermediate section 62, for example, between the outer partition 74 and the side wall 80. One or more other components may assist in maintaining the HM media 54 in a desired position relative to the inner partition 74 and valve mechanism 56. In addition, the inner partition 74 at least partially forms a first flow path (indicated by an arrow "A" in FIG. 4A) and a second flow path (indicated by an arrow "B" in FIG. 4B). It is a solid body. In particular, the inner partition 74 forms opposing first and second ends 84, 86, and the first flow path A is partially formed between the first end 84 and the lower wall 72. And a second flow path B is formed partially between the second end 86 and the top wall 70.

The first flow path A proceeds from the first port 58, through the HM medium 54, to the second port 60 (and vice versa), and thus may be referred to as the HME path. In one configuration of FIG. 4A, the HM medium 54 is sized and positioned within the housing 52 such that a gap 88 is formed between the HM medium 54 and the bottom wall 72, and the first flow path. (A) establishes a U-shaped path through the gap 88 and around the first end 84 of the inner partition 74. However, in other configurations, the HM media 54 may contact the bottom wall 72 (or the gap 88 may be removed).

The second flow path B runs from the first port 58, through the intermediate section 62, to the second port 60 (and vice versa) and does not include the HM medium 54. Thus, the second flow path B may be referred to as a bypass path. Bypass path B is around or on the side of HM media 54. Unlike conventional bypass HME units, the bypass path (ie, second flow path B) according to some aspects of the present invention does not “via” the HM medium 54, and thus more as described below. Enables implementation of user friendly valve configurations.

As indicated above, the HM media 54 is of size and shape located within the intermediate section 62. In this regard, the HM media 54 may take various forms known in the art that provide heat and moisture retention characteristics and are typically or include foamed materials. Other configurations, such as paper or filler type bodies, are also acceptable. In a more general aspect, the HM medium 54 may then be any material capable of retaining heat and moisture, and whether such material is employed for other functions (eg, filter particle (s)). Does not matter. In some configurations, HM media 54 has a generally rectangular shape, forming opposing first and second major surfaces 90, 92. In final assembly, the HM media 54 is arranged such that the first major surface 90 is fluid facing the first port 58, and the second major surface 92 is fluid facing the second port 60. . In other words, for the first flow path A, the first major surface 90 acts as a side where the air flow from the first port 58 initially interacts with the HM medium 54 and vice versa. Likewise), similarly, the air flow from the second port 60 along the first flow path A initially interacts with the second major surface 92 and vice versa. With this in mind and referring further to FIG. 4C, the HME unit 50 has a relatively large HM medium surface area (ie, first or second major surface 90, 92) with a first flow path (A). Although shown within, the HM media 54 is oriented such that the apparent air flow restriction is minimized. In particular, the flow along the first flow path A proceeds through the thickness T of the HM medium 54, where the thickness T is the length L or width W of the HM medium 54 (FIG. Smaller than 4c). In some embodiments, the gap 88 (provided fluidly adjacent to the second major surface 92) facilitates this desirable air flow characteristic. As such, resistance to breathing of the average patient through the HME unit 50 is minimized.

As indicated above, the valve mechanism 56 designates a flow path A or B in which at least primarily air flow between the ports 58, 60 will occur. In this regard, the valve mechanism 56 includes an air flow blocking member 100 that is movably disposed or assembled within the intermediate section 62 as best shown in FIGS. 4A and 4B. Other components related to some configurations of the valve mechanism 56 according to the present invention are described below. In addition, the obstruction member 100 may take various shapes and is generally provided as a solid body or bodies through which air flow cannot pass. In one configuration of FIGS. 4A and 4B, the blocking member 100 is plate-shaped, and alternatively, other valve blocking bodies (eg, ball valves, etc.) are also acceptable. In any case, the blocking member 100 is switchable between the first position shown in FIG. 4A and the second position shown in FIG. 4B. For example, in one configuration of FIGS. 4A and 4B, blocking member 100 is similar to a plate formed by tip end 102 and trailing end 104. The trailing edge end 104 is pivotally mounted in the housing 52 via, for example, a pin 106. Other switchable assembly configurations are also acceptable, such as by providing trailing end 104 as a living hinge. In this configuration, the switching of the blocking member 100 then includes the blocking member 100 pivoting at the trailing edge end 104 while the leading end 102 moves between the first and second positions. With this in mind, the tip end 102 is configured to engage or seal against the corresponding structure of the housing 52, for example the upper wall 70, in the first position of FIG. 4A. In other words, the blocking member 100 in the first position causes the blocking member 100 to close the second flow path B, thereby forcing all air flow to occur along the first flow path A, or The size and shape are determined to specify. Since the first flow path A includes the HM medium 54, the first position of the obstruction member 100 may be referred to as an "HME position" or "HME mode".

In some embodiments, the housing 52 and the valve mechanism 56 are configured to create a more streamlined passageway between the first port 58 and the HM medium 54 in the HME position. For example, the first port 58 forms a central axis C _P1 . In the first position of the blocking member 100, the blocking member 100 is arranged such that its main plane is substantially parallel to the central axis C _P1 of the first port 58, thereby disengaging the HM medium 54. Direct air flows directly (and vice versa). In other words, in the first position of the obstruction member 100, the air flow does not encounter a 90 ° corner between the first port 58 and the HM medium 54. Alternatively, another relationship between the first port 58 and the obstruction member 100 can be established.

Referring specifically to FIG. 4B, in the second position of the obstruction member 100, the proximal end 102 transitions away from engagement with the upper wall 70 (eg, pivots at the trailing edge 104), thereby removing the first end 102. The two flow paths B are not blocked by the blocking member 100. In particular, in the second position, the blocking member 100 does not completely block or close the first flow path A. FIG. For example, a gap 108 exists between the leading end 102 of the obstruction member 100 and the corresponding sidewall 80 of the housing 52. Stated differently, the housing 52 is the first passage opening 110 for the HM medium 54 along the first flow path A (eg, formed between the inner partition 74 and the side wall 80). And effectively create second passage opening 112 for second flow path (B). The obstruction member 100 has a size and shape corresponding to that of the second passage opening 112, and thus extends across the second passage opening 112 in the second position to close it. However, the size and shape of the blocking member 100 is smaller than that of the first passage opening 110 so that the blocking member 100 does not surround the entirety of the first passage opening 110. In other words, the blocking member 100 does not completely close the first flow path A, regardless of the position of the blocking member 100 relative to the housing 52.

In the second position of the obstruction member 100, the second flow path B is at least partially interrupted by the obstruction member 100, whereby the air flow is not in close contact with the HM medium 54. Freely proceed to and from the first and second ports 58, 60. Thus, the second position of the blocking member 100 may be referred to as a "bypass position" or "bypass mode". In the bypass position, air flow can still occur along the first flow path A via the gap 108. However, HM media 54 effectively serves to limit or resist air flow through gap 108. In particular, since the air flow will find the path of least resistance, in the bypass position of the obstruction member 100, almost the majority of the air flow will occur directly through or along the second flow path B. FIG. In fact, at least 95% of the air flow, at least 97% in other embodiments, and at least 98% in yet other embodiments, are the second flow path B when the blocking member 100 is in the bypass position as described below. It was surprisingly found to occur through).

In view of reference, the first position (FIG. 4A) and the second position (FIG. 4B) of the blocking member 100 as described above reflect the opposing first and second maximum moving points of the blocking member 100. FIG. do. For example, the first maximum point of movement may be associated with the top wall 70 to prevent the top wall 70 from moving (eg, clockwise rotation relative to the orientation of FIG. 4A) beyond the first position. By the tip end 102 (or other portion of the obstruction member 100) in contact. Conversely, the housing 52 may include stops or other features that prevent movement of the blocking member 100 beyond the second position (eg, counterclockwise rotation relative to the orientation of FIG. 4B), such that the second Form the maximum moving point. Alternatively, the HME unit 50 may be configured to establish a second maximum point of movement different from that of FIG. 4B (eg, the second position may include the blocking member 100 in contact with the HM medium 54). Can be). However, according to the principles of the present invention, at any position of the blocking member 100 relative to the housing 52, the blocking member 100 does not completely block or close the first flow path A. FIG.

In some embodiments, the valve mechanism 56 is configured to allow a user to manually perform the switching and locking of the blocking member 100 to a desired position or mode. For example, in some embodiments, valve mechanism 56 includes a biasing member 120, such as a torsion spring, which biases shutoff member 100 to a first or HME position. This arrangement simplifies the bypass mechanism and aids seal integrity independent of operator interaction / use (eg, the operator does not have to guess whether the HME location has been achieved). With further reference to FIGS. 3A and 3B, the valve mechanism 56 may further include an actuator arm 122 and an optional release device 124, all of which are accessible from the exterior of the housing 52. . Actuator arm 122 is coupled to blocking member 100 (eg, via pin 106) such that blocking member 100 moves (eg, pivots) with movement of actuator arm 122. Thus, the rotational position of the actuator arm 122 of FIG. 3A corresponds to the first position of the blocking member 100 shown in FIG. 4A. Conversely, the rotational position of the actuator arm 122 of FIG. 3B corresponds to the second position (bypass position) of the blocking member 100 shown in FIG. 4B. Thus, in order to switch the HME unit 50 from the HME mode (FIGS. 3A and 4A) to the bypass mode (FIGS. 3B and 4B), the user (not shown) must overcome the spring force or bias of the spring 120. The moment force is sufficiently applied onto the actuator arm 122, thereby causing the blocking member 100 to pivot or rotate from the HME position to the bypass position.

One or more features may be included to selectively capture and retain one or both of the obstruction member 100 and / or the actuator arm 122 in the bypass position. For example, release device 124 may be configured to releasably engage with actuator arm 122 as described below. In addition, if provided, the optional release device 124 is operable to selectively release the actuator arm 122 and the obstruction member 100 from the bypass position. As best shown in FIGS. 3A and 3B, the release device 124 may include a switch member 128 that is movably (eg, pivotally) mounted to the housing 52. The switch member 128 forms a contact surface 130 and engagement finger 132. The contact surface 130 is sized to easily receive a user's finger when operating or operating the release device 124 and is formed or provided opposite the attachment point 134 of the switch member 128 to the housing 52. . Engagement finger 132 is sized to selectively abut or connect with a corresponding feature of actuator arm 122. For example, in some embodiments, actuator arm 122 includes or forms head 140. With this approach in mind, the actuator arm 122 and the switch member 128 may have their head 140 (or other components associated with the head 140 such as latches) bypass the actuator arm 122 upon final assembly. When rotated to mode or position (FIGS. 3B and 4B), it is constructed and arranged to contact the engagement finger 132. In some embodiments, engagement finger 132 and head 140 are captured relative to each other in a bypass position or mode, thereby performing a temporary lock. In any case, the valve mechanism 56 may be released from the bypass position or mode by the user applying a force onto the contact surface 130. This applied force causes the switch member 128 to rotate relative to the attachment point 134, resulting in the engagement of the finger 140 and the actuator arm 122 away from the locked engagement in the bypass mode or position. To force (relax them). Alternatively or additionally, a pulling force can be applied by the user onto the head 140 to cause separation from the switch member 128 (or other locking device, if provided). When released, the biasing member 120 biases or forces the obstruction member 100 to the HME position.

HME unit 50 may include one or more additional features to facilitate the aforementioned movement of switch member 128. For example, the switch member 128 may further include a shoulder 142 (shown in FIG. 4A) extending opposite the contact surface 130 and may include a housing 52 (eg, a first port 58). ) Forms a slot 144 (FIG. 3A) that is sized to slidably accommodate the shoulder 142. In this configuration, the shoulder 142 / slot 144 connection then allows and guides movement of the switch member 128 in releasing the actuator arm 122 from the locked bypass position. Alternatively, shoulder 142 and slot 144 can be removed. The valve mechanism 56 may include other components configured to facilitate manual switching and locking of the blocking member 100 to a desired position or mode as described below.

HME unit 50 may include one or more additional optional features. For example, and with reference to FIG. 4B, the housing segments 76, 78 may be formed separately and selectively assembled with respect to each other. In this configuration, the HM media 54 can be easily accessed and replaced by simply removing the first housing segment 76 from the second housing segment 78. In addition, a secondary filter 150 may be provided. The secondary filter 150 can take various forms (eg, HMEF known in the art) and is assembled directly adjacent to the HM medium 54. In one configuration of FIG. 4B, the secondary filter 150 abuts the second major surface 92 of the HM medium 54 and thus has a relatively large filtration surface area corresponding to the surface area of the HM medium 54. Can be. In addition, the bypass feature of the HME unit 50 described above for the HM medium 54 is equally applicable for the secondary filter 150. Thus, secondary filter 150 may be bypassed in the same manner as HM media 54. Compared to previous HME devices that include a secondary filter or do not provide a filter separately from the HM media bypass feature, the secondary filter 150 according to the present invention is relatively large, enabling lower resistance and higher filtration efficiency. can do. In terms of reference, FIG. 4B shows a secondary filter 150 captured between the walls formed by the housing segments 76, 78 and supporting the HM media 54 in final assembly. It will be appreciated that the secondary filter 150 is an optional component in accordance with the present invention, and the HM media 54 can provide the desired filtration on its own.

A further optional feature provided to the HME unit 50 is the resistance indicator 160. The resistance indicator 160 may take a variety of forms and generally serves to identify when the differential pressure or resistance across the HME unit 50 (in HME mode) has exceeded a predetermined value. For example, as shown in FIG. 5, the resistance indicator 160 is in fluid communication with the second port 60 along the first flow path A, and thus the HM media (for the second port 60). 54) (FIG. 4A) is exposed to an internal pressure differential within the HME unit 50. Resistance indicator 160 may be mechanical (eg, a silicon diaphragm) and / or may include electronic components. In any case, when triggered (ie, in the presence of an excessive pressure differential across the HM medium 54), the resistance indicator 160 may display a warning or other indication of a potentially problematic condition of the HME unit 50. To the guardian (eg, HM medium 54 is obviously resistant to air flow). In this regard, where the resistance indicator 160 is disposed internally within the housing 52, the one or more outer walls 162 associated with the housing 52 and located very close to the resistance indicator 160 may be a resistor. The indicator 160 can be at least partially transparent so that the indicator 160 can be seen through the housing 52. In other embodiments, the resistance indicator 160 may be omitted.

3A-4B, an additional optional feature provided to the HME unit 50 is a check valve (not shown). The check valve is provided separately from the valve mechanism 56 and is described in more detail below for other HME unit embodiments. However, in a general aspect, the check valve is movably retained in the housing 52 along the second flow path B and through the second flow path B in the first flow direction (eg, the second port ( Air flow from the first port 58 to the second port 60 (eg, from the first port 58 to the second port 60) in the second opposite flow direction Air flow is configured to prevent.

Regardless of whether one or more of the optional features described above are provided, during use, the HME unit 50 may be a patient breathing circuit, such as the breathing circuit 10 of FIG. 1 or the breathing circuit of FIG. 40) in fluid connection. Patient tube 20 is fluidly connected to first port 58 and second port 60 is fluidly connected to a tubing connected to a ventilator (not shown). Thus, the first port 58 serves as the patient side port and the second port 60 serves as the ventilator side port. If no medicament is provided to the patient 12 via the respiratory circuit 10, 40 (ie, when the nebulizer 18 is not connected to and / or not operational with the respiratory circuit 10, 40), the HME Unit 50 is operated in HME mode (FIGS. 3A and 4A). Thus, air flow to and from patient 12 via HME unit 50 must pass through HM medium 54 (and optional secondary filter 150, if provided), with HM medium 54 Absorbs moisture and heat from exhaled air and then transfers the moisture and heat to the inhaled air provided to the patient's lungs.

When the nebulizer 18 is operated to administer the nebulized medication to the patient 12, the HME unit 50 causes the user to bypass the HME mode by pressing the actuator arm 122 (FIGS. 3B and 4B). Is easily switched to. When the blocking member 100 is in the bypass position, the air flow to and from the patient 12 via the HME unit 50 is due to the bypass flow path B (due to the resistance created by the HM medium 54). Along and thus around the HM medium 54 (and optionally a secondary filter 150, if provided) (eg, in terms of the HM medium). In the bypass mode, the likelihood that the HM media 54 is clogged with drug droplets is then virtually eliminated.

The ability of the HME unit 50 to function preferably as a bypass HME has been confirmed by testing. In particular, the non-limiting exemplary HME unit according to FIGS. 4A-4C is configured to include HM media formed from polyurethane foam and has a length L of 6.9 cm (2.75 inches), a width of 5.0 cm (2.0 inches) ( W), and a thickness T of 0.95 cm (0.375 inches). A secondary filter (ie, secondary filter 150) was further included in the form of polypropylene fibers and had a length and width corresponding to HM media and a thickness of 1.3 mm (0.050 inch). Finally, the housing and blocking member were configured such that the gap (ie, gap 108) was 3.8 mm (0.150 inch) in the closed or bypass position. The HME unit so configured was then tested by transferring air flow into the first or patient side port (i.e., port 58) and the flow rate along the HM flow path (i.e., HM flow path A) was increased to the patient side port (i.e. Opposite the HM medium, on the opposite side of the port formed along the bottom wall 72). Under these conditions, it was surprisingly found that at an air feed flow rate of 30 L / min, approximately 0.74% of the flow (when the blocking member is in the closed or bypass position) penetrated the HM medium / secondary filter. At an air feed flow rate of 60 L / min, approximately 1.13% of the flow penetrated the HM medium / secondary filter. Finally, at a maximum air feed flow rate of 77.5 L / min, approximately 1.25% of the flow passed through the HM medium / 2 secondary filter. Thus, it was surprisingly found that even if full flow isolation of the HM medium in the bypass state was not provided, the HME unit would function fully as a bypass HME unit.

The HME unit 50 described above is only one acceptable configuration in accordance with the principles of the present invention. For example, an HME unit 50 'of a related embodiment in accordance with the principles of the present invention is shown in FIG. 6, and is shown in FIGS. 6A and 7B although the housing 52', HM media 54 '(hidden in FIG. 6). Shown), and a valve mechanism 56 '(referenced generally). The housing 52 'forms a first port 58' (eg, a patient side port), a second port 60 '(eg, a ventilator side port), and an intermediate section 62'. The HM medium 54 'is retained in the intermediate section 62' and the valve mechanism 56 'has air flow at least primarily between the first and second ports 58', 60 ', as described below. It works to specify the path to proceed.

In particular, with reference to FIGS. 7A and 7B, the housing 52 ′ may comprise a first portion between the ports 58 ′, 60 ′, as indicated by arrow A of FIG. 7A and arrow B of FIG. 7B. And a second flow path. The first flow path A includes the HM medium 54 ′ and does not include the second flow path B. In other words, the air flowing through the first path A interacts with the HM medium 54 'and thus constitutes the HME path. Conversely, the air flowing in the second flow path B does not interact closely with the HM medium 54 'and thus serves as a bypass path. As in the previous embodiment, the second flow path / bypass path B is around (eg, on its side) the HM medium 54 '. In terms of reference, FIGS. 7A and 7B show a much more streamlined path (relative to the HME unit 50 described above) along the second flow path / bypass path B, wherein the first and second ports The central axes of 58 'and 60' are parallel and in some embodiments coaxial.

The valve mechanism 56 ′ includes a blocking member 100 ′ movably assembled within the housing 52 ′ as described above. However, compared with the HME unit 50 (FIG. 1), the valve mechanism 56 ′ has a different configuration for performing manual switching of the blocking member 100 ′ between the HME position of FIG. 7A and the bypass position of FIG. 7B. It includes. For example, the valve mechanism 56 'includes a biasing member 170 (FIGS. 7A and 7B), such as a torsion spring, which biases the blocking member 100' to the first or HME position. Furthermore, referring specifically to FIG. 6, the valve mechanism 56 ′ includes an actuator assembly 172 and a locking device 174. Actuator assembly 172 includes an actuator arm 176 rotatably mounted to and projecting from housing 52 '. Rotation of the actuator arm 176 relative to the housing 52 'effectes switching of the blocking member 100' (FIGS. 7A and 7B) as described below. Thus, actuator arm 176 is rotatable from the HME state or position of FIG. 6 to the bypass state or position (ie, clockwise rotation relative to the orientation of FIG. 6) and vice versa. In this regard, the locking device 174 is configured to contact and temporarily lock the actuator arm 176 in the bypass position or state.

For example, in some embodiments, the locking device 174 includes a pair of fingers 178a and 178b that protrude from the housing 52 '. Fingers 178a and 178b are naturally biased in the orientation reflected in FIG. 6, whereby fingers 178a and 178b inherently resist deformation towards each other. In addition, fingers 178a and 178b are sized to be selectively captured within opening 180 (generally referred to) formed by actuator arm 176. In particular, when actuator arm 176 is rotated toward fingers 178a, 178b, fingers 178a, 178b are actuated by actuator arm 176 in a bypass position or state, for example, due to the natural deflection of fingers 178a, 178b. And retain him selectively by interlocking within). If desired, the actuator arm 176 can be "released" from the temporary lock state by the user simply lifting the actuator arm 176 and rotating the actuator arm 176 away from the fingers 178a, 178b.

Further referring to FIGS. 7A and 7B, the actuator arm 176 is connected to the blocking member 100 ′ via the pin 182 and the attachment body 184. The attachment body 184 connects the pin 182 with the blocking member 100 'and is also mounted to the actuator arm 176. In this configuration, rotation of the actuator arm 176 is transmitted to the blocking member 100 ′ via the pin 182 and the attachment body 184. Alternatively, other mechanisms for interconnecting the actuator arm 176 and the blocking member 100 'are also acceptable.

Another embodiment of the HME unit 200 according to the invention and useful as the HME unit 16 (FIGS. 1 and 2) is shown in part in FIGS. 8 and 9. The HME unit 200 is similar to the HME unit 50 (FIG. 3A) described above and includes a housing 202, an HM medium 204, and a valve mechanism 206. The housing 202 forms a first port 208 (eg, a patient side port), a second port 210 (eg, a ventilator side port), and an intermediate section 212. The HM medium 204 can take any one of the forms described above and is retained in the intermediate section 212, and the valve mechanism 206 is configured to provide air flow to the first and second ports as described below. Acts to specify a path that at least primarily proceeds between 208 and 210.

The housing 202, and in particular the intermediate section 212, includes opposing outer wall segments 214, 216 and at least one inner partition 218. The inner partition 218 is spaced apart from the lower wall segment 216, thereby establishing a gap 220. In addition, the inner partition 218 forms an opening 222 adjacent the upper wall segment 214 to which the valve mechanism 206 is associated, as described below. In this configuration, the housing 202 then directs the first and second flow paths between the ports 208, 210, as indicated by arrow A in FIG. 8 and arrow B in FIG. 9. Form. The first flow path A includes the HM medium 204 and the second flow path B does not. In other words, the air flowing through the first flow path A interacts with the HM medium 204 and thus constitutes the HME path. Conversely, the air flowing in the second flow path B does not interact closely with the HM medium 204 and thus serves as a bypass path. As in the previous embodiment, the second flow path / bypass path B is around (eg, on its side) the HM medium 204.

The valve mechanism 206 includes a blocking member 230, for example a valve plate, as described above, movably assembled within the housing 202. The blocking member 230 is sized and shaped to selectively surround or close the opening 222, and the valve mechanism 206 may, in some embodiments, include the blocking member 230 in the interior partition 218 and in particular the opening 222. And a stem 232 movably associated). Thus, the obstruction member 230 is switchable between the first or HME position (FIG. 8) and the second or bypass position (FIG. 9). In the HME position, the obstruction member 230 is fitted with respect to the inner partition 218, thereby closing the second flow path B. In other words, at the HME location, only the first flow path A is “opened” between the first and second ports 208, 210, whereby air flow through the HME unit 200 causes the HM medium 204 to flow. Specifies to connect with. Conversely, in the second bypass position, the obstruction member 230 is spaced apart from the inner partition 218 such that air flow may occur through the opening 228. Thus, in the bypass position, the second flow path B opens to allow direct air flow between the first and second ports 208, 210 at or around the HM medium 204.

8 and 9 show the opposing maximum moving point of the blocking member 230 relative to the housing 202. Although the HME unit 200 may be modified to provide a maximum point of movement different from that of FIG. 9, the maximum point of movement so generated (or any intermediate position of the blocking member 230) may be such that the valve plate 230 may be of the first type. Do not allow flow path A to be completely blocked or closed.

Although not shown, the valve mechanism 206 may include one or more additional features that allow the user to guide the shutoff member 230 to a position corresponding to the desired mode of operation (ie, HME mode or bypass mode). . For example, the valve mechanism 206 may include a biasing device and / or an actuator arm as described above. Alternatively, any other mechanism (essentially mechanical, electro-pneumatic, and / or electrical) can be employed.

If the breathing circuit (not shown) to which the HME unit 200 is assembled does not provide an aerosolized medicament, the HME unit 200 is provided with the blocking member 230 positioned in a first position (FIG. 8). 2 is operated in HME mode to close flow path (B). Thus, the air flow through the HME unit 200 (between ports 208, 210) interacts with the HM medium 204, which absorbs moisture and heat from the exhaled air of the patient. And acts like a typical HME unit by the HM medium 204 which delivers moisture and heat to the intake air provided to the patient.

Conversely, if the breathing circuit in which the HME unit 200 is fluidly connected operates to provide the nebulized medication to the patient, the HME unit 200 has the blocking member 230 having an internal partition 218 / opening 222. Switch to a bypass mode (FIG. 9) that is spaced farther away. While the first flow path A remains " opened " in the bypass position or mode of the obstruction member 230, most of the air flow through the HME unit 200 will occur along the second flow path B. . In particular, as described above, the HM medium 204 presents a resistance to air flow, and in the bypass mode, in the bypass mode, the air flow between the ports 208, 210 because the air flow will find a path of least resistance. Almost all of will occur directly along the second flow path (B).

Although not shown, the HME unit 200 may include one or more of the additional optional features described above with respect to the HME unit 50 (FIG. 3A). Similarly, other optional features described below, such as check valves, may be included.

Another embodiment HME unit 250 in accordance with the principles of the present invention and useful as HME unit 16 (FIGS. 1 and 2) is shown in part in FIGS. 10 and 11. Once again, HME unit 250 includes a housing 252, an HM medium 254 (omitted from the figures of FIGS. 10 and 11, but generally indicated at its location), and valve mechanism 256. The housing 252 defines first and second ports 258, 260 extending from opposite sides of the intermediate section 262. HM medium 254 is disposed within intermediate section 262, and valve mechanism 256 specifies the path through which air flow between ports 258 and 260 is directed, at least primarily.

Housing 252 includes an outer wall segment 264, and at least one inner partition 266. The inner partition 266 is spaced apart from the outer wall segment 264, thereby forming a first flow path A (FIG. 10) and a second flow path B (FIG. 11). As in the previous embodiment, the first flow path A includes the HM medium 254 and the second flow path B does not. Thus, the first flow path A is the HME path and the second flow path B is the bypass path. As in other embodiments, the second flow path / bypass path B is around (eg, on its side) the HM medium 254.

The valve mechanism 256 is movably assembled within the housing 252 and includes a blocking member 270 (eg, a valve plate) configured to selectively close the second flow path B. In particular, in the first or HME position (FIG. 10) of the blocking member 270, the tip end 272 of the blocking member 270 contacts the outer wall segment 264, thereby allowing the first and second ports ( 258, 260 “close” second flow path B. Thus, in the HME position, blocking member 270 causes all air flow between ports 258 and 260 to occur along the first flow path A only.

Conversely, in the second or bypass position of the blocking member 270, the tip end 272 is diverted away from the outer wall segment 264, thereby directing the second flow path B (to the blocking member 270). Open). In the bypass position, the obstruction member 270 does not perform closing of the first flow path A, so that in the bypass mode of the HME unit 250, air flow through the HM medium 254 may occur. However, as described above, the HM medium 254 presents a resistance to air flow, so in the bypass mode, the air flow will find the path of least resistance, and thus mainly occur along the second flow path B. will be.

The positions of FIGS. 10 and 11 represent the opposing maximum moving points of the blocking member 270 relative to the housing 252. Although the HME unit 250 may be modified to provide a second maximum point of movement different from that of FIG. 11, the maximum point of movement so generated (or any intermediate position of the blocking member 270) may be It does not completely block or close the first flow path A.

Switching of the obstruction member 270 by the user between the first and second positions can be facilitated in a number of ways. In some configurations, valve mechanism 256 includes a biasing device (not shown) such as a spring that biases shutoff member 270 to a first or HME position (FIG. 10). Actuator arm 274 is pivotally assembled to housing 252 and forms first and second ends 276 and 278. The first end 276 extends outwardly from the housing 252 and the second end 278 bears against the blocking member 270. In one such acceptable configuration, the blocking member 270 is then switched from the HME position (FIG. 10) to the bypass position (FIG. 11) by the user by applying a rotational or moment force onto the first end 276. Can be. Rotation of the actuator arm 274 eventually causes the second end 278 to be held against the blocking member 270 in a cam-like manner and cause movement of the blocking member. Rotation of the actuator arm 274 in the opposite direction removes the force applied by the actuator arm 274, thus allowing the biasing device to force the obstruction member 270 back to the HME position. Alternatively, a wide variety of other components can be employed to allow the user to select the desired location or mode of operation.

In addition to the above, FIGS. 10 and 11 illustrate optional check valve features provided to the HME unit 250. In view of reference, the check valve feature described below is equally applicable in any one of the other HME unit embodiments described herein. With this in mind, the check valve feature includes a check valve mechanism 290 having a check valve plate 292. The check valve plate 292 is assembled in the housing 252 to selectively close the second flow path (B).

For example, in some configurations, the housing 252 is located between the first and second ports 258, 260 along the second flow path B and defines an opening 294 defined by the perimeter 296. Form. The check valve plate 292 is sized and shaped according to the size and shape of the opening 294 so that when positioned relative to the perimeter 296, the check valve plate 292 closes the opening 294. In this regard, the check valve plate 292 moves freely away from the opening 294 in the presence of gas flow in the first direction of flow along flow path B, and the presence of gas flow in the opposite flow direction. It is positioned and assembled to close to the opening 294 in the city. For example, referring specifically to FIG. 9, the air flow along the second flow path B in the flow direction from the second port 260 to the first port 258 causes the check valve plate 292 to open. Pivots away from 294, thereby allowing air flow along the second flow path B to occur freely. Conversely, the air flow along the second flow path B in the flow direction from the first port 258 to the second port 260 forces the check valve plate 292 to engage the perimeter 296. Thus, the opening 294 is closed. Thus, even if the blocking member 270 is in the bypass position of FIG. 11, the check valve plate 292 is the second flow (ie only in the presence of gas flow from the first port 258 to the second port 260). By periodically closing the path B, the air flow takes place in this direction only along the first flow path A.

The optional check valve mechanism 290 described above can, in some embodiments, improve the performance of the HME unit 250. For example, during use, HME unit 250 may be connected to a patient breathing circuit (not shown) such that first port 258 serves as the patient side port and second port 260 serves as the ventilator side port. Can be assembled. With this designation in mind, when the HME unit 250 is in bypass mode, drug droplet entrained air flow from the ventilator side port 260 to the patient side port 258 occurs primarily along the second flow path (B). In other words, the blocking member 270 and the check valve plate 292 do not block air flow from the ventilator side port 260 to the patient side port 258. As such, by patient inhalation, drug droplets are delivered to the patient's lungs and are not in obvious contact with the HM medium 254. However, due to the patient exhalation, the direction of air flow changes (ie, moves from the patient side port 258 to the ventilator side port 260), so that the valve plate 292 opens the opening 294 as described above. To close. The exhaled air thus proceeds through the HM medium 254 where heat and moisture are captured and retained. Even if there is air exhaled from the patient, because of the minimal drug droplets, any blockage of HM media 254 is greatly minimized.

Another embodiment of the HME unit 300 according to aspects of the invention and useful as the HME unit 16 (FIGS. 1 and 2) described above is shown in FIGS. 12 and 13. HME unit 300 includes a housing 302, an HM media 304, and a valve mechanism 306. The housing 302 defines first and second ports 308, 310 and an intermediate section 312 extending therebetween. The HM medium 304 is retained in the intermediate section 312, and the valve mechanism 306 operates to specify a flow path where at least primarily air flow between the ports 308, 310 will occur.

The intermediate section 312 includes an outer wall segment 314 and at least one inner partition 316. The inner partition 316 is spaced apart from other components of the housing 302 to establish a first flow path A and a second flow path B. FIG. For example, the inner partition 316 may partially establish passages 318a and 318b in which air flow along the first flow path A may occur. In any case, the HM medium 304 is disposed along the first flow path (A). Conversely, the second flow path B is spaced apart (eg, around or on its side) from the HM medium 304. Thus, the first flow path A constitutes an HME path and the second flow path B is a bypass path.

The valve mechanism 306 may take various forms and, in some embodiments, includes a blocking member 330 (eg, a valve plate) movably assembled within the housing 302. In particular, the blocking member 330 is movably positioned to selectively "close" the second flow path B. For example, the housing 302 can define an opening 332 along the second flow path B defined by the wall perimeter 334. The blocking member 330 is in the first or HME position (FIG. 12) such that the blocking member 330 abuts against the wall circumference 334 to close the opening 332 and the second flow path B, Size and shape depending on the size and shape of the opening 332. Conversely, in the second or bypassed position (FIG. 13) of the blocking member 330, the blocking member 330 is spaced away from the opening 332 / wall periphery 334 so that the blocking member 330 is the opening 332. ) And the second flow path (B) are not blocked. In the bypass position, air flow between the first and second ports 308, 310 can then occur directly along the second flow path B. As in the previous embodiment, in the bypass position, the blocking member 330 is in the bypass mode so that air flow to the HM medium 304 along the first flow path A can occur, such that Does not explicitly block). However, due to the resistance presented by the HM medium 304, the air flow will follow the path of minimum resistance, and in the bypass position (FIG. 13), the air flow occurs at least mainly along the second flow path B. .

The positions of FIGS. 12 and 13 represent the opposing maximum points of movement of the obstruction member 330 relative to the housing 302. Although the HME unit 300 may be modified to provide a second maximum point of movement different from that of FIG. 13, the maximum point of movement so generated (or any intermediate position of the blocking member 330) may be It does not completely block or close the first flow path A.

As in the previous embodiment, the valve mechanism 306 can take various forms, and various features for effecting the switching of the blocking member 330 between the first and second (or HME and bypass) positions. Contains wealth. For example, in some embodiments, the valve mechanism 306 includes a stem 336 that slidably holds the blocking member 330 relative to the opening 332. In addition, other components may be provided, such as springs (not shown) and external actuators (not shown) that provide the user with the ability to select the desired position of the blocking member 330 and the operating mode of the HME unit 300. Can be.

Another embodiment of the HME unit in accordance with the principles of the present invention and useful as the HME unit 16 (FIGS. 1 and 2) is shown in FIGS. 14 and 15. HME unit 350 is similar to HME unit 300 (FIGS. 12 and 13) described above and includes a housing 352, an HM medium 354, and a valve mechanism 356. Housing 352 defines or defines first and second ports 358, 360 extending from opposite sides of intermediate section 362. HM medium 354 is disposed within intermediate section 362. The valve mechanism 356 operates to specify a flow path in which air flow between the first and second ports 358, 360 will occur at least primarily.

The housing 352 includes an outer wall segment 364 and at least one inner partition 366. The inner partition 366 is spaced apart from other components (eg, the outer wall segment 364) to form the first and second flow paths A and B. For example, the interior partition 366 may partially establish passages 368a and 368b in establishing the first flow path A. As shown in FIG. In any case, the HM medium 354 is located along the first flow path A, and the second flow path B is spaced apart (eg, at or around the HM medium 354). Thus, the first flow path A constitutes an HME path and the second flow path B is a bypass path.

The valve mechanism 356 can take various forms that can specify the open or closed state of the second flow path (B). For example, in some embodiments, the valve mechanism 356 may include an opening formed by the housing 352 along the second flow path B (eg, between the partition 366 and the corresponding wall segment 364). A blocking member 380 (eg, valve plate) positioned to selectively close 382. In the first or HME position (FIG. 14) of the blocking member 380, the blocking member 380 surrounds or closes the opening 382, thereby blocking the second flow path B. FIG. Thus, in the HME position (or HME operating mode), the air flow between the first and second ports 358, 360 only occurs along the first flow path A and therefore must pass through the HM medium 354. do). Conversely, in the second or bypassed position (FIG. 15) of the blocking member 380, the blocking member 380 is moved away from the opening 382 so that the second flow path B is opened by the blocking member 380. It is no longer blocked. However, as in the previous embodiment, in the second or bypass position, the first flow path A is completely by the blocking member 380 such that air flow can occur along both flow paths A and B. It is not blocked. However, in the bypass position (or bypass mode of the HME unit 350), the HM medium 354 presents resistance to air flow, and because the air flow will find the path of least resistance, ports 358 and 360. The air flow between them will mainly occur along the second flow path (B).

The positions of FIGS. 14 and 15 represent the opposing maximum points of movement of the obstruction member 380 relative to the housing 302. Although the HME unit 350 can be modified to provide a maximum point of movement that is different from that of FIG. 15, the maximum point of movement so generated (or any intermediate position of the blocking member 380) is such that the blocking member 380 is firstly positioned. Do not allow flow path A to be completely blocked or closed.

In some embodiments, the valve mechanism 356 is configured to provide a check valved feature. In particular, the valve mechanism 356 includes additional components (not shown) that selectively act on the blocking member 380. In terms of reference, the blocking member 380 may be described as including a pivot end 384 and a free end 386. Movement of the blocking member 380 relative to the opening 382 includes a blocking member 380 pivoting at the pivot end 384. With this approach in mind, the components of the valve mechanism 356 can operate in the HME mode of operation so that the free end 386 is locked or locked in the first position of FIG. 14. As described above, the first or HME position of the obstruction member 380 causes air flow through the HME unit 350 to occur only along the first flow path A. FIG. In the bypass operating mode, the components of the valve mechanism 356 release the blocking member 380 relative to the opening 382 so that the blocking member 380 can pivot freely at the pivot end 384. In the bypass mode of the valve mechanism 356 when the HME unit 350 is assembled in the patient breathing circuit such that the first port 358 serves as the patient side port and the second port 360 serves as the ventilator side port. The blocking member 380 pivots freely away from the opening 382 by patient inhalation (ie, gas flow in the direction from the second port 360 to the first port 358). Thus, the blocking member 380 minimizes the delivery of the aerosolized medicament to the patient when the patient inhales. In other words, by the air flow in the flow direction from the ventilator side port 360 to the patient side port 358, the obstruction member 380 opens the second flow path B. By the patient exhalation (ie, the direction of flow from the patient side port 358 to the ventilator side port 360), the air flow forces the obstruction member 380 back to the closed position relative to the opening 382, thereby Exhaled air carries HM media 354 (and optional filters (not shown)). At the next patient inhalation, the blocking member 380 is freely opened again.

Regardless of the exact design, the HME unit of the present invention provides a significant improvement over previous designs. The HME unit provides a viable HME and bypass mode of operation. However, unlike conventional bypass HME unit designs, the HME unit of the present invention is compact and streamlined, and user switching between HME and bypass mode is easily achieved (e.g., frictionally fitted housing components are mutually compatible with each other). Is not required to be rotated). In addition, the HME unit is relatively inexpensive to manufacture and is easily configured to include additional features such as filters and the like.

Although the invention has been described with reference to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims (23)

Heat and moisture exchange (HME) unit,
A housing defining a first port, a second port, and an intermediate section extending between the first and second ports, the intermediate section defining first and second flow paths that fluidly connect the first and second ports With housing,
Heat and moisture retention media (HM media) maintained in the intermediate section along the first flow path,
A valve mechanism movably retained within the housing, the valve mechanism including a blocking member switchable between opposing first and second maximum movement points,
The HME unit closes the second flow path such that the blocking member induces air flow only through the first flow path at the first maximum travel point, and at the second maximum travel point, the blocking member is connected to both the first and second flow paths. Configured to allow air flow through,
HME unit. The method of claim 1, wherein the HM medium comprises opposing first and second major surfaces, the HM medium being positioned within the housing such that the first major surface is in fluid facing the first port and the second major surface is in fluid facing the second port. And at any position of the blocking member, the blocking member does not completely block fluid communication between the first major surface and the first port or between the second major surface and the second port. The HME unit of claim 1, wherein the HM media has a width greater than the length and thickness exceeding the width, and wherein the HM media is arranged such that the first flow path is through the thickness of the HM media. The HM medium of claim 1, wherein the HM medium has opposing first and second major surfaces separated by minor side surfaces, wherein the HM medium has a first major surface in fluid facing the first port and a second major surface in the first surface. 2 HME unit arranged for the first flow path in fluid contact with the port. The housing of claim 4, wherein the housing includes at least one outer wall and at least one inner partition that are combined to form at least a portion of the first flow path, wherein the first and second major surfaces are spaced apart from the wall of the housing. HME unit. The HME unit of claim 5, wherein each of the minor side surfaces of the HM media abuts at least one of the walls of the housing. The HME unit of claim 5, wherein the first flow path is U-shaped in cross section. 8. The HME unit of claim 7, wherein the U-shaped first flow path is at least partially formed by the bottom wall of the housing, while the HM media is spaced apart from the bottom wall. The flow path of claim 1, wherein each of the first and second flow paths comprises a passage opening adjacent to the first port, and the blocking member is disposed proximate the passage opening, and wherein the size of the blocking member is a passage of the second flow path. An HME unit that is larger than the size of the opening and smaller than the size of the passage opening of the first flow path. The HME unit of claim 1, wherein the valve mechanism includes a spring that biases the blocking member to the first maximum point of travel. The valve mechanism of claim 10, wherein the valve mechanism further comprises an actuator arm accessible from the outside of the housing and connected to the blocking member, wherein the actuator arm is configured to divert the blocking member from the first maximum movement point to the second maximum movement point. HME unit. The HME unit of claim 11, wherein the valve mechanism further comprises a release switch configured to selectively engage the actuator arm upon switching of the blocking member to the second maximum point of travel. The HME unit of claim 12, wherein the release switch is accessible from outside of the housing and is configured to release the actuator arm in response to a user applied force. The HME unit of claim 1, wherein the HM media forms a major plane, and in final assembly, the central axis of the second port is substantially parallel to the major plane, and the central axis of the first port is not parallel to the major plane. . The method of claim 1,
A check valve mechanism comprising a check valve plate movably retained within the housing along a second flow path
In addition,
The check valve mechanism is configured such that the check valve plate allows air flow through the second flow path in the first flow direction and prevents air flow through the second flow path in the second opposite flow direction,
HME unit. The HME unit of claim 15, wherein the check valve plate is spaced apart from the blocking member. The HME unit of claim 16, wherein the check valve mechanism is configured to lock the check valve plate in an HME operating mode. The method of claim 1,
Secondary filter placed in middle section adjacent to HM media
HME unit further comprising. The HME unit of claim 18, wherein the secondary filter is maintained along the first flow path. The HME unit of claim 1, wherein the middle section comprises an upper segment and a lower segment, wherein each of the ports extends from the upper segment, and the HM media is disposed within the lower segment. Heat and moisture exchange (HME) unit,
A housing defining a first port, a second port, and an intermediate section extending between the first and second ports,
A heat and moisture retaining medium (HM medium) that forms opposing first and second major surfaces, wherein the HM medium is such that the first major surface is in fluid facing the first port and the second major surface is in fluid facing the second port. HM media, disposed in the housing,
A valve mechanism comprising a blocking member movably assembled in an intermediate section fluidly between the first major surface of the HM medium and the first port,
The blocking member is switchable from the HME position where the blocking member completes the HME flow path from the first port through the HM medium to the second port and closes the bypass flow path around the HM medium,
The HME unit is configured such that at any position of the blocking member relative to the housing, at least a portion of the first major surface of the HM media remains fluidly open to the first port,
HME unit. Heat and moisture exchange (HME) unit,
A housing defining a first port, a second port, and an intermediate section extending between the first and second ports, the intermediate section defining first and second flow paths that fluidly connect the first and second ports With housing,
Heat and moisture retention media (HM media) maintained in the intermediate section along the first flow path,
A single secondary filter maintained in the intermediate section along the first flow path,
A valve mechanism movably assembled within the housing, the valve mechanism including a blocking member that is switchable between a first position in which the first flow path is opened and the second flow path is closed and at least a second position in which the second flow path is opened; and,
The HM unit and the secondary filter are spaced apart from the second flow path. 23. The method of claim 22, wherein the HM medium forms a plurality of outer faces at least one of which has a maximum surface area relative to the rest of the plurality of outer faces, and wherein the surface area of the outer face of the secondary filter forms a maximum surface area. HME unit approximating the area of the outer surface.

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